The invention relates to the perforation, in particular the puncture of a membranous member while utilizing vacuum fixation. Such a method may be applicable to veterinarian techniques or techniques which involve the determination of the exact composition of substances which are located on either side of an elastic, possibly permeable membrane e.g. by taking a sample. In medicine, when the general method of vacuum fixation is used, the protection of the invention may extend to the device which causes the vacuum fixation of a tissue subjected thereto before it is perforated or punctured respectively.
The necessity to take samples from specimen e.g. which are surrounded by one or more elastic foils is well-known in laboratory research. In order to prevent possible contamination while sampling, e.g. by bacteria, it may be desirable to take a sample very cautiously via flexible membrane walls which act like a sterile sluice as it were. A similar sampling occurs also during the cultivation of specific organisms, whether or not in connection with multiplication or for research into syndromes or impacts of other materials. In all these cases the intended vacuum fixation is applicable.
The object of the invention is to perforate the membranous member at the eact location, while utilizing vacuum fixation, in particular to puncture without causing of undesirable damages or undesirable contamination inside the space which is enclosed by the membranous member.
The method according to the invention is based on the transfer of a specific amount of solid, gaseous or fluid medium to or from a space through an enclosing, flexible membranous member which is enclosed by said membrane, thereby utilizing a suction force that is applied on part of the membrane surface, resulting in a locally increasing yet allowable deformation by tensioning of said surface, after which the locally pre-tensioned membrane is punctured by means of an instrument, in particular a needle-shaped instrument, the required amount of medium is transferred with respect to said space through a supply or drain tube fixed in or at said instrument, and the instrument is then withdrawn from the membrane surface puncture, the local suction force then being released and whereafter the membrane elastically returns to its original position.
Vacuum fixation while utilizing puncture technique includes several possibilities. The invention can be used to perform a Douglas puncture e.g. to obtain peritoneal fluid. When a Douglas puncture is performed, it can happen that the tissue of the back part of the vagina dome and the Douglas peritoneum, which is located behind it, give way in the direction of the abdominal cavity. In that case, danger arises that other tissues, e.g. the intestines, will be punctured inadvertently and unintendedly, which can give rise to infection. Due to these dangers, one is obliged to operate through surgery in order to obtain peritoneal fluid, practically exclusively by means of laparoscopy.